High-R Duct Insulation =

Energy Saving Comfort Delivery System Insulation

Uninsulated ducts can experience significant heat loss or heat gain through the walls of the ducts, especially if the ducts are located in an uninsulated attic or crawlspace. Energy-saving comfort delivery system insulation protects the conditioned air flowing through the ducts from heat loss or heat gain when traveling from the comfort equipment to the living spaces of the home.

Alternate Terms

Energy Saving Comfort Delivery System Insulation Sales Message

Energy saving comfort delivery system insulation reduces the heat gain and lost getting heating and cooling to each room. What this means to you is less wasted energy getting comfort to each room. Wouldn’t you agree it’s important that your comfort delivery system is insulated for optimum performance?

Climate

No climate specific information applies.

Description

Ideally ducts should be located in conditioned space, such as within a dropped ceiling, between floors, in an insulated basement or crawlspace, or in an unvented attic that is insulated along the roof line.

Whenever ductwork is located in unconditioned spaces, thermal insulation with a vapor barrier is a must to prevent unnecessary heat gain or heat loss through the duct walls and to prevent condensation from forming on the ducts themselves. Supply ducts located in unconditioned space should be insulated to at least R-8; all other ducts should be insulated to at least R-6. For the insulation to work properly, it must be fully aligned and in contact with the ducting. A typical vented attic with a dark shingle roof can reach summer temperatures of 140ºF. At the same time, the dew point temperature in the attic will be about the same as it is outdoors. In humid climates, "duct sweating" can become a significant problem if the ducts’ thermal and vapor barriers are not properly aligned along the entire length of the ducts, including at all duct connection points.

How to Install Ducts with Adequate Insulation Levels in Unconditioned Space:

Determine duct layout at the design stage to allow for a compact duct layout with open duct chases or routes that provide adequate space and support so that ducts can be routed with no compressions and with as few bends as possible.

For metal ducts – select R-8 or higher insulation for supply ducts; select R-6 or higher insulation for return ducts and other ducts. Install metal ducts using the installation guidance provided in Sealed and Insulated Metal Ducts. See this guide or the insulation manufacturer’s recommendations for “stretch-out” guidance to ensure adequate insulation thickness.

Ensuring Success

After ducts are installed and before drywall is installed, the duct system should be visually inspected by a HERS rater to ensure that the ducts have the proper amount of insulation. Supply ducts located in unconditioned space should be insulated to at least R-8; all other ducts should be insulated to at least R-6. The inspector should also confirm that the insulation is properly installed to fully cover the ducts along their entire lengths and that the insulation is not missing or compressed anywhere along the duct length.

Section 403.2.1 Insulation (Prescriptive). Supply ducts in attics are insulated to a minimum of R-8. All other ducts in unconditioned spaces or outside the building envelope are insulated to at least R-6.*

Section R403.2.1 Insulation (Prescriptive). Supply ducts in attics are insulated to a minimum of R-8. All other ducts in unconditioned spaces or outside the building envelope are insulated to at least R-6.*